Triple return dryer

Introduction to Three way Drying Machine

The three return dryer is an efficient combined three cylinder dryer. The overall structure is made up of three interlocking conical cylinders welded in different directions and sequences. This special structural form determines its production capacity, so this new type of dryer is also called a three pass dryer. The three return dryer is mainly used to dry granular materials within a certain humidity range, such as yellow sand used in the dry powder mortar industry and various specifications of molding sand used in the casting industry. Blast furnace slag used in the building materials and cement industry. Small particle clay is used in the chemical industry for small particle materials that do not undergo chemical changes, are not afraid of high temperatures, and are not contaminated by smoke and dust. According to the requirements of different industries for the final moisture content of dried materials, the moisture content of dried materials can reach below 1-0.5%.

Working principle of three return dryer

Like other drying equipment, the three return dryer uses a feeding device to feed materials into the inner layer of the rotary drum, achieving downstream drying. The materials are continuously picked up and scattered under the inner layer's plate, forming a spiral motion for heat exchange. The materials move to the other end of the inner layer and enter the middle layer for countercurrent drying. The materials are repeatedly lifted in the middle layer, forming a two-step forward and backward motion. The materials not only fully absorb the heat emitted by the inner drum, but also absorb the heat from the middle drum, while extending the drying time. The materials reach an excellent drying state here. The material reaches the other end of the middle layer and falls into the outer layer. The material travels in a rectangular multi loop manner in the outer drum. The material that achieves the drying effect quickly travels out of the drum under the action of hot air. The wet material that does not achieve the drying effect cannot move quickly due to its own weight. The material is fully dried in this rectangular plate to achieve the drying purpose.

Process flow diagram of three return dryer

The sand flows from the wet sand bin into the belt conveyor through the disc feeder and is sent to the hopper. It then enters the dryer through the sand flow pipeline. The slope of the sand flow pipeline should be greater than the natural inclination angle of the material, so that the material can flow smoothly into the dryer. The dryer cylinder is a rotating cylinder slightly inclined from the horizontal line. The material is added from the higher end, and the heat carrier enters from the lower end, coming into counter current contact with the material. The heat carrier and the material flow together into the cylinder. As the cylinder rotates, the material moves to the lower end under the action of gravity. During the forward movement of the wet material inside the cylinder, it directly or indirectly receives heat from the heat carrier, allowing the wet material to dry, and then is sent out through a belt conveyor or screw conveyor at the discharge end. The inner wall of the sand dryer cylinder is equipped with a copying plate, which is used to pick up and sprinkle the material, increase the contact surface between the material and the airflow, improve the drying rate, and promote the material to move forward. Thermal carriers are generally divided into hot air, flue gas, etc. After passing through the dryer, the heat carrier generally needs a cyclone dust collector to capture the materials carried in the gas. If further reduction of exhaust dust content is required, it should also be discharged after passing through a bag filter or wet dust collector.

Advantages of Three way Drying Machine

1. The investment in the three return dryer is 20% of imported products from abroad, and it is made of wear-resistant manganese plate, which is 3-4 times more wear-resistant than ordinary steel plate.
2. The initial moisture content of the material is 15%, and the final moisture content is ensured to be below 0.5-1%. It is an essential product for various drying projects such as cement plant slag powder and dry powder mortar production lines.
3. Improved thermal efficiency by over 40% compared to traditional single drum dryers.
4. The fuel can be used for white coal, bituminous coal, coal gangue, oil, and steam. Capable of drying block, granular, and powdered materials below 20-40mm.
5. Reduce the footprint by about 60% compared to a single drum dryer. Reduce civil engineering investment by about 60% and facilitate installation.
6. No air leakage phenomenon, completely solving the sealing difficulty.
7. If the discharge temperature is ≤ 60 degrees, it can be directly fed into the material warehouse without the need for cooling in the cooling shed.
8. The temperature of the outer cylinder is ≤ 60 degrees, the temperature of the exhaust gas is<120 degrees, and the use time of the dust removal equipment bag is more than twice as long. Coal consumption is 1/3 of that of a single drum dryer, saving 40% of electricity, and consuming less than 9 kilograms of standard coal per ton.

Technical parameters of three return dryer

Note: The equipment model parameters are constantly being improved. If you cannot find the required model in the parameter table, you can contact us directly. Our technicians will configure the equipment that best suits your production needs and site requirements according to your requirements.